Change-speed gearbox

ABSTRACT

638,301. Controlling change-speed gearing. MAGIS, A. A. G. May 29, 1947, No. 14278. Convention &#39; date, April, 8, 1943. [Class 80 (ii)] In change-speed gearing having constant-mesh gear pairs brought selectively into action by dog clutches all situated on one gearing shaft, the clutches are actuated by sliding normally to the shaft a common operating member having on opposite sides of the shaft duplicate cam plates with cam grooves or slots engaged by diametrically opposed trunnions on each clutch fork. As shown, applied to a motor vehicle, an input pinion 4, Fig. 1, drives through a gear 14 a layshaft 16 carrying gears 15 meshing, directly or through a reversing idler 17, gears 6 connectible to the output shaft 2 by dog clutches 5 slidably splined thereon. Trunnions 11, Fig. 2, on the clutch forks 10 engage cam slots 12, Fig. 3, in the side plates 13 of an operating member connected by arms 18, slidable in the gear casing, to an operating bell-crank lever 20, 19 co-acting with a notched quadrant 25. Stops 27 prevent movement of the forks 10 perpendicular to the shafts. Movement of the lever arm 19 in one direction gives successive gear ratios from reverse to fourth speed or vice versa, with a neutral position between each ratio. As applied to a bicycle bottom bracket gear, pinions 31, Fig. 10, clutchable to the crank shaft 30, mesh pinions 33 rigid with a layshaft driving through further gear pairs 35, 36 a&#39;shaft carrying the chain wheel 38. An operating member 41 controls the clutches 32 as before to give four forward speeds. Gearing according to the invention is also applicable to rolling mill trains or machine tools and, when used for the latter, two gears of the kind having parallel driving and driven shafts may be employed in series to give multiple ratios.

2 1953 l A. A. G. MAGIS 2,660,070

CHANGE-SPEED GEARBOX I Filed Dec. 26, 1947 2 Sheets-Sheet l 0 F- .2Fig.1 25 25 INVENTOR.

Auguste Adelin Gushve Mnq'Is NOV. 24, 1953 A GLMAG|$ 2,660,070

' CHANGE-SPEED GEARBOX Filed Dec. 26, 1947 2 Sheets-Sheet 2 INVENTOR.

Amius'k Adelin Gue'lnwe Mqqis M 4m 1W Patented Nov. 24, 1953 UNITEDSTATES PATENT OFFICE In France- April' 8', 1943 Section 1, Public Law690, August 8, 1946 Patent; expires April 8, 1963 1 Claim.

The present invention relates to change-speed gearboxes of the type inwhich the gear wheels are constantly meshed.

An improved change-speed gearbox according to the invention, havingconstantly meshing gears some of which are connected to a shaft and theothers, rotatably mounted on a second shaft parallel with the first one,are coupled to this second shaft by displacements of dog clutchesslidably mounted upon it, includes ramps or cam surfaces adapted tocontrol the displacements of each dog-clutch, the various ramps beingsuitably staggered and connected to a common operating member in such away that to each operative position of such member corresponds apredetermined combination of positions of the dog-clutches andconsequently a similarly predetermined ratio of speed transmission.

Preferably the operating member is constituted by a pair of plates eachcontaining as many cam grooves or slots as there are dog-clutches to becontrolled and each groove is engaged by a finger adapted to act on thecorresponding dogclutch, the edges of the grooves having at suitablepoints notches which compel the corresponding clutches to slide in onedirection or the other. In order to couple them together each free gearand the corresponding dog-clutch may be provided with lateral teeth ontheir adjacent faces and one and the same clutch is preferably toothedon both its faces so as to serve for two speeds.

The working of a change-speed gearbox constructed in accordance with thepresent inverttion is simple and reliable, and a single lever providedwith a locking device may serve to control the movements of the groovedplates or grids. Since all the wheels rotate continuously, engagementtakes place only between wheels the speeds of which are very similar,there being thus practically no shock or noise during engagement. Theshafts are consequently very short as also the dog-clutches which needonly be of such width as is imposed by the rate of wear of the metalemployed.

Clutching by means of lateral teeth permits the amount of space occupiedto be reduced to a minimum, since the width of the teeth may be verygreat and their depth very small. The gear is silent and simple inoperation, and is thus suitable for motor vehicles as well as formachine (,Cl. PL-337.51

2 tools for precision work and large output, rolling mills and the like.

This change-speed gearbox is suitable for all powers and for all speeds.When used on a bicycle it may weigh less than a kilogram but it mayattain a weight of several tons when used on a very large rolling mill.train. In comparison with the gearboxes usual on modern cars, its lengthmay be reduced by 40%.

The present gearbox may be provided with wheels having spur, helical orskew teeth, and the shafts may be provided with any of the known typesof bearings.

Two embodiments of the invention will be described by way of examplewith reference to the accompanying drawings in Which:

Figure 1 is a View partly in section in the plane of the shafts of achange-speed gearbox for a motor car having four speeds and reversedrive;

Figure 2 is a section at right angles to the shafts of the same gearbox;

Figure 3 shows in elevation the grid which serves to move the slidingpinions;

Figure 4 is an end view thereof;

Figure 5 is a side view of one of the dogclutches;

Figure 6 is a front view thereof;

Figure 7 is a side view of a fork for operating one of the dog-clutches;

Figure 8 is a vertical section on the line VIII- VIII of Figure 7;

Figure 9 is a part sectional side view of a four speed gearbox suitablefor a bicycle; and

Figure 10 is a section in the plane of the shafts of the same gearbox.

Referring now to the drawings and more particularly to Figures 1 to 3,the driving shaft l is in line with the main shaft 2, both being mountedin the casing 3 by the usual means. One end of the main shaft 2 rotatesin a socket provided for it in the driving shaft I. This latter carriesa toothed wheel 5. On the main shaft 2- are strung successivelydog-clutches 5 and pin ions ii. The clutches. 5 are driven by the mainshaft 2 by means of keys 8 on which they are adapted to slide, while thepinions rotate loosely on the main shaft 2 from which they are separatedby rings 1. Finally the dog-clutches are provided with forks it thetrunnions H of which (see Figure'2) ride in cam rooves l2 formed in thetwo flanks of a grid l3. The pinions i and 5 gear with theircorresponding wheels It and l5 mounted on a lay shaft IS. The gearwheels are always in engagement.

The reverse drive is effected through the medium of an idler pinion I!which meshes with two others carried by the main shaft 2 and the layshaft I6 respectively.

The grid i3 is provided with two arms I8 which project from the casingfor control of its movement. A lever l9, associated with connecting rods20 and shafts 2i and 22, permits of imparting to the grid It thesuccessive positions corresponding to each of the speeds desired.

A suitable locking device ensures the locking of the grid and thereforeof the dog clutches in each of their positions. The drawings show aconstructional form employing quadrants 25 notched at is. The lateralfaces of the dog clutches carry straight lateral teeth 26 (Figures 1, 5and 6), and identical teeth are reproduced on the lateral faces of thecorresponding pinions.

When the lever i9 is operated, one of the dog clutches is broughttowards its pinion by the action of the corresponding grooves in thegrid. Engagement of the clutch occurs at a speed which is very similarto that of the pinion, and as soon as the lateral teeth are broughtopposite the spaces in the other series of teeth, they engage and themain shaft receives the whole of the power transmitted by the drivingshaft. Vv'hen the lever i9 is moved over still further, the dog clutchis thrown out of gear. The action is instantaneous and requires only avery slight effort owing to the fiat faces of the lateral teeth andtheir small depth. Stops 2? fix d to the casing 3 limit the movement ofthe forks during movement of the grid.

The positions of the axes of the forks relatively to the grid is shownin Figure 3, and these combined positions determine the profile of thegrooves which are to be cut in the flanks of the grid.

In the example elected, in fourth speed, the grid is fully inserted inthe casing and the trunnions H or" the right hand fork are carriedcompletely to the right of the groove. On pushing the lever into thesecond notch, the three pairs of trunnions will be brought into linewith the axes of the grooves and none of the wheels is in engagement.The third speed is obtained by pushing the lever further, which bringsthe tworight-hand trunnions to the left of the righthand groove.Movement of the lever is to the next notch brin s the whole system intothe neutral position and all the trunnions are again aligned with theaxes of the grooves. At the fifth notch, the gear is in second speed andthe second dog clutch has been brought to the right of the axes of itsgrooves. At the next notch, disengagement takes place, all the trunnionsbeing brought back into the axes of the grooves. In first speed, thecentral trunnions are moved towards the left. All the trunnions arebrought back into line with the axes of the grooves for the Eastdisengagement and finally, at the last notch, the mechanism is inreverse gear, the left-hand trunnions being displaced towards the rightof the left-hand grooves.

The succession of speeds is obtained therefore by simple and easilyperformed movements of a lever in a single plane.

Figures 9 and 10 show a gearbox suitable for a bicycle, its operationbeing identical but the construction slightly different.

The pedals 29 of the bicycle are secured on a driving shaft 30 on whichare mounted, as previously indicated, pinions 3! and dog clutches 32.Pinions 33 are keyed on a lay shaft 34 which also carries, keyed on it,pinions 35 the function of which is to transmit power through pinions 36to a main shaft 37, on the end of which is mounted the chain wheel 38 ofthe bicycle over which the chain 39 passes. Forks it are moved by a grid4| through the medium of shafts t2 and 43, connecting rods 44 and t5,and a rod it. The locking mechanism (not shown) is preferably placednear the handle-bar. The gearbox takes the place of the pedal bottombracket at the intersection of the lower tube M, the saddle tube :18 andthe tubes 49 of the bottom fork.

When the gearbox is to be used for a machine tool, two shafts aresumcient and the lay shaft is combined with the main shaft and transmitsthe power of the engine.

To obtain a large series of speeds which would require shafts of alength incompatible with the resistance of the metal, two or moregearboxes may be combined with each other. Two gearboxes of six speedseach will provide for example 6 X 6:36 speeds. If an odd number ofspeeds is required, it is sufficient to use only one face of a dogclutch, as shown in the gearbox for a motor car for the position ofreverse gear. There is no need to adopt an increasing or decreasingorder of speeds, as they may succeed each other in any order whatsoever.

Modifications in details may be made in the change-speed gearbox justdescribed without thereby departing from the scope of the presentinvention.

I claim:

In a change-speed gear box of the type including a rotatable shaft, anumber of gears mounted in predetermined axial relationship upon andkeyed to the shaft for rotation therewith, rotatably mounted shaft meansdisposed parallel and adjacent to the shaft, the same number of pinionsfreely rotatably mounted in predetermined axial rclationship upon theshaft means, and a plurality of clutches axially slidably keyed to theshaft means, the improvement comprising: said gears and pinions beingaxially arranged in units each consisting of a gear and pinion always inmeshed relationship with each other, each pinion having one side faceproximate to one side face of a clutch, said proximate side faces beingprovided with complementary driving means, said side faces beingengageable in driving relationship upon axial displacement of the clutchtoward the pinion whereby torque applied to the pinion may go throughthe clutch to said shaft means, a yoke for each clutch, each clutchbeing axially movable into or out of pinion engagement under the forceof its yoke, a pair of cam followers on each yoke disposed substantiallydiametrically with respect to the associated clutch, the line defined byeach pair of cam followers being at all times substantially parallel tothe line defined by each other pair of cam followers, a pair ofsubstantially parallel cam plates disposed one on one side of the shaftmeans and the other on the other side of the shaft means and eachsubstantially perpendicular to the lines defined by said cam followers,a plurality of pairs of cam grooves in said plates one groove of eachpair being in one plate and the other groove of each pair being in theother plate, each pair of cam followers being associated with a pair ofcam grooves, said cam plates being constrained to translatory movementeach substantially within its own plane, and cam locking structurearranged to fix said cam plates in a selected position so as to fix saidyokes and the associated clutches each in a, predetermined relationshipwith respect to said pinions.

AUGUSTE ADELIN GUSTAVE MAGIS.

References Cited in the file of this patent Packard Nov. 4, 1902 NumberNumber Name Date Loitron Oct. 23, 1908 Allen Oct. 11, 1910 Ringer July10, 1917 Carbone Jan. 22, 1924 Weinreich June 16, 1936 Chandler Oct. 13,1942 Kummich Dec. 29, 1942 FOREIGN PATENTS Country Date Great BritainJune 21, 1911 Switzerland Apr. 1, 1939

